Field of the Invention
The present invention concerns a method to acquire magnetic resonance data, as well as a magnetic resonance system, and an electronically readable data storage medium.
Description of the Prior Art
Magnetic resonance MR is a known modality with which images of the inside of an examination subject can be generated. Expressed in a simplified manner, for this purpose the examination subject in a tunnel opening of a magnetic resonance apparatus is positioned in a strong, static, homogeneous basic magnetic field (also called a B0 field) with a field strength of 0.2 to 7 Tesla or more, such that nuclear spins in the subject orient along the basic magnetic field. Radio-frequency (RF) excitation pulses and possible refocusing pulses are radiated into the examination subject to trigger magnetic resonance signals, which are detected and entered as data values into an electronic memory, in an organized manner that represents a domain known as k-space, such as a matrix. On the basis of the k-space data, MR images are reconstructed or spectroscopy data are determined. Rapidly switched (activated) magnetic gradient fields are superimposed on the basic magnetic field for spatial coding of the magnetic resonance data (measurement data). The acquired measurement data are digitized and stored as complex numerical values in k-space matrix. For example, by means of a multidimensional Fourier transformation, an associated MR image can be reconstructed from the k-space matrix populated with values.
Artifacts can occur in the acquisition of magnetic resonance data for imaging, particularly in the acquisition of data from the examination subject in planes that proceed essentially orthogonally to the middle axis of the tunnel opening, for the purpose of generating a cross-sectional image.
Such artifacts have previously been avoided by the entirety of k-space corresponding to the subject to be imaged being scanned (filled with data) repeatedly, and the magnetic resonance data that are thus obtained have been averaged. However, this leads to an increase of the total measurement time by up to 40%, which is unacceptable in an everyday clinical environment.